Live-cell biosensor for assessment of adhesion qualities of biomaterials

The present study describes a live-cell biosensor, suitable for general evaluation of adhesion qualities of different substrates. It is based on NIH/3T3 fibroblast cell line stably expressing fusion fluorescently tagged proteins mCherry-vinculin and GFP-tensin as quantifiable markers for assessment not only of focal but also of fibrillar contacts. Four measurable parameters - spreading, polarization and development of focal and fibrillar adhesions were used to standardize the adhesion of biosensor cells after plating on five substrates of natural origin - fibronectin, vitronectin, laminin-111, laminin-521 and collagen type I. The obtained set of values (adhesion quality map) were utilized to describe the default biosensor behavior and as a standard for evaluation of surface biocompatibility of materials with unknown adhesive properties. To demonstrate the applicability of the biosensor we studied two PDMS-based artificial materials. The results demonstrated the superior adhesive properties of the poly(acrylic acid)-containing polymer (PDMS-PAA) over that of poly(vinyl pyrrolidone) copolymer (PDMS-PVP), and pointed out the formation of focal adhesions as a parameter for possible further improvements.